FIELD OF THE INVENTION
This invention relates to the sharpening of blades and more particularly to sharpeners for electric razor blades.
As with almost any type of cutting surface, the life and utility of a rotary blade is enhanced if it can be occasionally resharpened. Various types of rotary blades are known including, for example, rotary shaving blades, such as those incorporated in a NORELCO electric razor.
Prior attempts have been made to provide for sharpening such blades. Some such attempts are seen in the patents to one Raymond R. Wheeler (U.S. Pat. Nos. 2,953,851; 3,163,964 and 3,163,965 in particular). In these prior art teachings, it is proposed to bring a blade and honing disc into contact and thereafter rotate the blade or the disc to sharpen the blade cutting edge.
The first and last of the above-mentioned patents are particularly representative of prior efforts that illustrate the need for the improvements to be disclosed herein. In U.S. Pat. No. 2,953,851, a cup containing a honing ring is brought to the blade within the razor housing. In U.S. Pat. No. 3,163,965, a cup is carried by a cup that telescopes over the cup to guide and center the blade and honing ring. In this unit the cap is to be received within the razor's head.
In all these prior art structures, the only way to prevent blade damage during sharpening is to be extremely careful to watch the pressure used to bring blade and honing disc into contact. This means that it is difficult to obtain a correct angle of address of the blade and honing disc as any degree of pressure other than the correct amount can deform the spokes carrying the cutting surfaces.